Sparking device



i l l United States Patent "ice vSPARKING DEVICE v l ernar'd C. Fisher, Jersey City, NJ., assigner to Neutronic Development Corporation, Englewo'od,N.J., a corporation, of New Jersey l Application June 18, 19`58,.Serial No. 742,830

6 Claims. (Cl. 313--11.5)

This invention relates to sparking devices -for internal Patented Nov., 1 7,.l 15959 -serted in the shell and the end of the portion 2 of the combustion engines and has for itsprincipal object to i provide a sparking device which will provide improved efliciency of operation of the engine with vwhich it is fused. i

Another object of the invention is to provide a sparking device which Awill operate at a lower temperature than devices heretofore used with better control -of the spark and less tendency for the formation of carbon.

Another object of the inventionis to provide a sparking device having a skirted insulator in which the `temperature of the `skirt is maintained below a predetermined maximum and electrical shorting over the rimofv the skirt is prevented.

The invention is illustrated in the accompanying drawings, in which: o

Figure l is a sectional elevational view Vof the sparking device of the invention;

Figure 2 is a sectional plan view of the device; taken on the line 2-2 of Figure l;

Figure 3 isa sectional plan view of the device taken onthe line 3-3 of Figure l; and t Figure 4 is an enlarged view of a portion of a cartridge which is an important inner part of the 'device before rolling and compressing.

VThe sparking device of the invention provides a com# bustion space inside the device in which the .fuel mixture first ignites and produces a blow torchi effect, r-`

ing the mixture in the combustion space of the cylinder substantially instantaneously. TheV size and shape of this internal combustion space is critical and aids intheV Figure l shows the sparking devi-ce ofthe invention as comprising a metallic shell 1, preferably `of steel, having an outer surface of two different diameters. The main portion 2 has the larger diameter and is provided with a hexagonal outer rim 3 to receive a socket ywrench for screwing the device into thecylinder block of an internal combustionV engine. The portion 4 of. smaller diameter is threaded to tit into the tapped hole'fin the cylinder block provided 'for it. l

The thickness of the shell at both portions 2 and 4 may be about the same, forming a cylindrical inner surface 5 for the main portion 2 and a cylindrical inner surface 6 for the portion 4 with a bevelled portion 7 connecting the two surfaces.

An insulator 8 has a main cylindrical portion 9, -slightly smaller in diameter than the inside of the portion 2 of the shell, and a length slightly less than 4the inner length of said portion. The insulator ts in the shell 1 with the main portion 9 of the insulator within the portion 2 of the shell. The insulator has a tapered portion 10 extending within the portion-tf of the shell to a point near the end of the portion 4 thereof. Between the tapered portion 10 and the main portion 9 is a bevelled surface |11 having the same slope as the bevelled surface shell is rolled over, as at 16, to hold the insulator securely within the shell with a gas-tight connection.

'Phe insulator 8 has a bore extending through it having different diameters. That portion 17 of the bore within the `tapered portion .10 has straight sides extending a short distance into the main portion 9 of the insulator. This portion of the bore cooperates with the outer `tapered wall of the portion 10 to form a skirt having a narrow rounded end 18 a short distance from the,l end of the portion 4 of the shell.

In the main portionV 9 of the insulator there is a short*l portion. 19 of the bore which is approximately half the lengthof the main portion 9 and has a diameter smaller than the other bore portions. This portion 19 of the bore joins'the portion 17 with a rounded shoulder 20.,v The portion 21 ofthe bore extending through the extended portion 12 of theinsulator has a diameter approximately the same as the portion 17 and joins the portion 19 with a rounded shoulder 22. The outer end of the bore portion 21 is enlarged and threaded to receive a threaded portion 23 of a stud 24 which is smaller in diameter than the bore portion 21 and, when screwed into position,v

extends to -a` point just short of the inner end of the bore portion 21.

i A conductive glass sealing member' 25 is positioned within the bore portion 19 and extends? from the shoulderl 2-0 to a'point just beyond the end of the stud'24. V.This member is made of glass into which is embedded paru ticles of a metal, such as silver, and is fused into `posi-- tion' so that it completely seals the bore against the passage of gases therethrough.

A conducting rod 26 extends from the sealing lmem-2 ber. ZS'toV a point just beyond the end of the shell'portion 4 and forms one of the sparking electrodes. This rod is secured in position by aA porous conducting mem-V ber 27 which forms an important part ofthe invention. The member 27 is formed of a rectangular sheet of fine metal wires woven into cloth and then rolled into acyl-- inderor cartridge with a hole axially through thecenter, toaccommodate the rod 26v and then die pressed. The, wires are preferably made of copper `in ribbonV for'rn and the completed cylinder is of just the right size so that itcan Ibe inserted under pressure into the lbore portion 17: Where it lies in-close contact with the rod26, the' inner-"wall of the bore portion 17, and the conductive glassisealingmember- 25. Thus, a good-electricalconf' tact4v is. formed-between the conducting-rod 26'andf lthe conductive glass sealing member 25. When pressed into. place, the member 27 with the rod 26 inserted thereiniills the space Within the bore portion 17 and secures the... -rod in position.

The member 27, which I call a copper Basterite car. tridge, has an important elfect on the operation of the. sparking device. Although it appears to occupy a large-- portion of the space within the bore portion 17, it is1 actually porous because of the interstices between the individual wires and therefore forms part of the firing space referred to above. Since the wires are a good heat conductor, heat will ow into it from the rod 26 andi from the insulator skirt of the insulator portion 4. Be. cause of the porous nature of the member 27, there is ai relatively large surface from which the heat may pass,.- into the surrounding gases and materials so as to diss` sipatethe heat during intake and compression strokes. Thus, the skirt and rod 26 are prevented from overheating, with the result that the device operates much cooler than spark plugs now in use and with much less carbon formation. In addition, the porous nature of the member 27 causes it to have a certain amount of resiliency, so that it never can exert enough pressure under the expansion of heat against the walls of the insulator to cause them to crack in operation.

In operation, the cartridge 27 seems to actV like an inductance, increasing the intensity ofthe spark over that produced by the same device in the same electrical .circuit but without the cartridge.

If desired, the end of the insulator extension may be provided with tins 28. These fins increase the electrical path between the central conductor and the shell to prevent ashover. v

I also provide a collar 29 of Bakelite or other material less rigid than the ceramic of the insulator. This collar tits snugly over the insulator against the shell andmay be provided with circular ribs 30, as shown. Thepurpose of the collar is to protect the insulator when a socket wrench is placed over the insulator to screw the sparking device into position in the cylinder block. If the wrench is tilted while in this position, the inside surface will strike the ribs of the collar before touching the insulator.

In assembling the cartridge 27, I place a neopreneasbestos gasket 31 on the end thereof which is held thereon by friction with the wall of the insulator. Thishas the effect of protecting the cartridge until the wires thereof have become oxidized. When the device is used, the neoprene immediately burns off and the asbestos remains as a porous layer.

The dimensions and shape of the interior, of the firing space of the device are critical, as explained in the patent referred to above, although of course they may vary Somewhat for engines of diierent size and compression rates. For an ordinary, high compression, automobile engine, the following dimensions for the internal tiring space were found to give good results:

' Inches Internal diameter of shell portion 4 .387 Length of shell portion 4 from gasket 15 to end .4375 Diameter tapered portion adjacent gasket 15- 0.380

Diameter tapered portion 10 at end 0.320 Length tapered portion 10 from gasket 15 to end 0.532 Diameter of bore 17 0.205 Length of bore 17 0.750 Length of cartridge 27 0.50 Width of cartridge wire from 0.020 to 0.030 Thickness of cartridge wire from 0.003 to 0.005 Diameter of rod 26 0.068 Extension of rod 26 beyond end of shell 0.03125 Diameter of bore 19 0.101

'Ihe operating temperature of the end of the skirt may be controlled by the length of the cartridge Z7. If the cartridge is made longer, the end of the skirt and the center electrode will operate at a lower temperature.

While one embodiment of the invention has been shown and described, modications may be made without departing from the spirit of the invention. I do not therefore wish to limit my invention except by the limitations contained in the appended claims.

What I desire to claim and secure by Letters Patent 1. A sparking device for an internal combustion engine comprising a tubular metallic shell, an insulator within said shell and having a skirt thereon extending towards Vone open end of said shell, a conducting rod positioned within said skirt terminating adjacent the end of said shell, means providing an electrical conducting path through said insulator to said conducting rod, a porous conducting member within said skirt surrounding said conducting rod and in contact therewith and with the inner Walls of said skirt, and a ground conductor attached to one end of said shell and cooperating with said rod to form a spark gap.

2. A sparking device, as dened in claim l, in which the porous vconducting member tills a portion only of the space within the skirt..

3. A sparking device, as dened in claim 2, in which the porous conducting member is formed of metal wire, woven into cloth, rolled into a cylinder, and compressed.

4. A sparking,r device, as defined in claim l, in which the conducting rod is independent of the electrical conducting means through the insulator but is held in contact with the inner endthereof by the porous conducting Y member.

5. A sparking device, as defined in claim l, in which the porous conducting member comprises a flat sheet of Woven copper ribbon, rolled into a cylinder with a holey through the center for the conducting rod, and compressed into the space within the skirt so that it is in contact with the inner wall of said skirt and said conducting rod.

6. A sparking device for an internal combustion engine comprising a shell, an insulator within said shell, a conductor extending through said insulator and terminating adjacent the end of said shell, a ground conductor attached to said shell and cooperating with the end of said conductor to form a spark gap, said insulator having a skirt spaced from the walls of said shell and from said conductor and terminating adjacent the spark gap end of said shell, and porous conducting means within said skirt and in contact with said conductor for controlling the temperature of the end of said skirt and the tendency- References Cited in the le of this patent 1 UNITED STATES PATENTS 2,269,076

Boll Jan. 6, 1942 2,499,823 Gogel Mar. 7, 1950 2,615,441 Bychinsky Oct. 28, 1952 2,680,432 Rand June 8, 1954 i 

